A Syrian official says security forces are advancing on the rebel-held neighborhood of Baba Amr in the restive central city of Homs.

Homs, and particularly Baba Amr, have been heavily shelled by tanks, artillery and rockets for weeks already by security forces trying to quell the 11-month-old uprising to oust President Bashar Assad. But the statement on Wednesday indicated a ground offensive was under way.

Activists say hundreds of people have been killed in the area since Feb. 4, when the assault on Homs began. Activists and residents inside Baba Amr could not be reached early Wednesday.

The official, who spoke on condition of anonymity in line with regulations, vowed Baba Amr would be “cleaned” within hours.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP’s earlier story is below.

BEIRUT (AP) – A wounded British photographer who had been trapped in the besieged Syrian city of Homs was spirited safely into Lebanon on Tuesday in a risky journey that killed 13 rebels who helped him escape the relentless shelling and gunfire.

A Syrian diplomat stormed out of an emergency U.N. meeting amid renewed calls for a cease-fire to deliver humanitarian aid. A top human rights official said a U.N. panel’s report concluded that members of the Damascus regime were responsible for “crimes against humanity.”

The United Nations said the death toll in the 11-month uprising against authoritarian President Bashar Assad was well over 7,500, and activists reported more than 250 dead in the past two days alone – mostly from government shelling in Homs and Hama province.

Tunisia’s president – the first since the country’s own Arab Spring uprising toppled his predecessor – offered the Syrian leader asylum as part of a negotiated peace, an offer Assad will almost surely refuse.

The harrowing ordeal of British photographer Paul Conroy, who was wounded with a French colleague last week by government rockets that killed two others, has drawn focus to the siege of Homs, which has emerged as the center of the anti-Assad uprising.

Hundreds have been killed in the city, parts of which the army has surrounded and shelled daily for more than three weeks. Many have died while venturing outside to forage for food, and activists have posted videos online of homes reduced to rubble and alleyways rendered no-go zones by snipers.

Conroy’s escape was the first sign of relief for a group of Western journalists who sneaked into Syria illegally and reached the embattled Homs neighborhood of Baba Amr only to find themselves trapped. Government rockets bombarded the makeshift media center they shared with activists last week, killing two of them and injuring Conroy and French reporter Edith Bouvier. Conroy and Bouvier later appeared in activist videos lying on makeshift hospital beds, pleading for help.

Conroy crossed the border into neighboring Lebanon after leaving Homs on Sunday evening, according to the global activist group Avaaz, which said it organized the evacuation with local activists.

The group said 35 Syrians volunteered to help get the journalists out and 13 were killed in the operation.

French President Nicolas Sarkozy retracted an earlier statement that Bouvier had also made it to Lebanon. He said he had been “imprecise” due to the complexities of the situation.

“It is not confirmed that Madame Bouvier is today safe in Lebanon,” he said.

The journalists believed to still be in the neighborhood are Frenchman William Daniels and Spaniard Javier Espinosa. In addition, the bodies of American Marie Colvin and French photographer Remi Ochlik, who were killed last week, are thought to be still in the neighborhood.

Syria’s conflict started in March 2011, when protesters inspired by the uprisings that ousted dictators in Tunisia and Egypt took to the street in impoverished hinterlands to call for Assad’s downfall. As his troops have used increasing force to try to stop the unrest, the protests have spread, and some demonstrators have taken up arms to protect themselves or attack the regime.

U.N. political chief B. Lynn Pascoe said “well over” 7,500 people have died in Syria’s violence and that there are credible reports that more than 100 civilians are dying daily. Activist groups said Monday the death toll for 11 months of unrest has surpassed 8,000.

The new U.N. death toll adds nearly 2,000 dead to last month’s toll of 5,400, suggesting an acceleration in the killing.

At a meeting in Geneva, U.N. High Commissioner for Human Rights Navi Pillay said the situation in Syria had deteriorated rapidly in recent weeks and called for an immediate humanitarian cease-fire.

She said her office has received reports that Syrian security forces “have launched massive campaigns of arrest.”

Pillay cited a U.N. expert panel’s report that concluded Syrian government officials were responsible for “crimes against humanity” committed by security forces against opposition members. The crimes included shelling civilians, executing deserters and torturing detainees. Some opposition groups, too, had committed gross abuses, the report said.

The panel has compiled a confidential list of top-level Syrian officials who could face prosecution over the atrocities.

Pillay reiterated her call for Syria to be referred to the International Criminal Court “in the face of the unspeakable violations that take place every moment.”

“More than at any other time, those committing atrocities in Syria have to understand that the international community will not stand by and watch this carnage and that their decisions and the actions they take today ultimately will not go unpunished,” she said.

Secretary of State Hillary Rodham Clinton, testifying in the Senate on Tuesday, said Assad fits the definition of a war criminal, but she stopped short of saying the international community should make that designation and level charges, pointing out that such a step is often a disincentive for leaders to step down.

Syria’s U.N. ambassador in Geneva, Fayssal al-Hamwi accused members of the U.N. Human Rights Council of promoting terrorism and prolonging the crisis by organizing the debate on the situation in his country.

Al-Hamwi denounced a planned resolution on Syria as “malicious and prejudiced,” and then said his delegation would withdraw from what he called “this sterile discussion.” He then stormed out of the room.

Eileen Chamberlain Donahoe, the U.S. representative to the 47-nation council, called al-Hamwi’s comments “delusional.”

“Anybody who heard the Syrian ambassador should be aware that his comments were borderline out of touch with reality,” she told reporters.

The U.N. said former Secretary-General Kofi Annan, the new U.N. special envoy to Syria, will meet in New York on Wednesday with current U.N. chief Ban Ki-moon.

Tunisia’s first post-revolution president, Moncef Marzouki, said he would offer Assad asylum as part of a negotiated end to the conflict. But Assad, who blames the uprising on Islamist extremists and armed gangs, is unlikely to accept the offer.

Conroy’s surprise arrival in Lebanon was celebrated by his family and British officials, who said they were trying to repatriate him.

“I have spoken to Paul this morning and he sounded in good spirits,” Conroy’s wife Kate Conroy said in a statement. “The family are overjoyed and relieved that he is safe and look forward to getting him home.”

She told The Associated Press by phone that she wouldn’t comment further for fear of jeopardizing the safety of those still attempting to leave.

Conroy, 47, and a father of three, is “in good shape and good spirits,” said his employer, The Sunday Times.

Britain’s Foreign Secretary William Hague said Conroy was “safely in Lebanon, where he is receiving full consular assistance.”

Britain’s ambassador to Lebanon, Tom Fletcher, said in a message on his Twitter account that Conroy’s experience was “a chilling testimony to what families in Homs (are) experiencing.”

The French reporter Daniels was last seen in an amateur video posted by activists last week, standing next to Bouvier, who was lying on a couch. He appeared uninjured. Bouvier works for Le Figaro.

Espinosa, who works for El Mundo, last sent a tweet Sunday that linked to a photo he said was from the Baba Amr neighborhood, showing blood pooled in a gutter.

Spain’s Foreign Ministry said it is trying to help to evacuate Espinosa. The newspaper said it does not know if he is injured and last spoke to him Monday.

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Associated Press writers Elaine Ganley in Paris, Frank Jordans in Geneva, Bouazza Ben Bouazza in Tunis, Tunisia, Donna Cassata in Washington, and Anita Snow at the United Nations contributed to this report.